Air pollution in the UK is ‘the greatest environmental risk to public health’, so why aren’t government targets more ambitious?
By
In 2014, residents of the Barbican Estate in central London reported seeing a black dust that, despite regular cleaning, was a permanent fixture on shelves and window ledges in their homes. They were understandably concerned about what they might be breathing in, and what it might be doing to their health.
Across the UK, an annual average of 5.6 per cent of deaths are attributed to long-term exposure to air pollution – roughly 30,000 a year. In London, it’s higher; nine per cent in the City of London and more than eight in Westminster, Kensington, Chelsea and Tower Hamlets. So when the City of London Corporation approached residents in the capital’s largest residential area, the Barbican, about a year-long citizen science project to collect and map local air quality, many were keen to be involved.
Over the past 50 years, London’s air pollution has changed. Technology and legislation, such as the 1956 Clean Air Act, have significantly reduced the lethal smog, caused by domestic and industrial coal burning, that still clouds the streets of Delhi and Beijing. Today, one of the major sources of UK air pollution is the rise in passenger road vehicles, responsible for nitrous oxides and fine particulate matter – including dust, smoke and soot – less than ten micrometres in diameter (for comparison, 90 micrometres is the size of a grain of sand). Together, they are the most damaging pollutants to human health.
When Barbican residents tested the air outside their bedroom windows and on their balconies, at their bus stops and along high-walks in the estate (at a total of 69 sites), they found that the level of nitrogen dioxide was above the EU legal limit – 40 micrograms per cubic metre – in more than half the locations. Nationwide, levels remain illegally high in more than three-quarters of urban areas. Last year, the World Health Organization sharply reduced its guideline upper limits for air pollution; down from 40 to ten micrograms for nitrogen dioxide and from ten to five micrograms for particles less than 2.5 micrometres in size (PM2.5). In March, when the UK government announced that its new air pollution target for PM2.5 would be double that recommended by the WHO, and wouldn’t come into effect for another 20 years, many campaigners criticised the measure as inadequate.
Evidence suggests there’s no safe limit for air pollution, but it can be a difficult problem to tackle, says William Bloss, professor of atmospheric science at the University of Birmingham. ‘It needs determined political engagement and action at a local and national level, and it’s not always something that people can see and perceive as a priority.’ The growing availability of low-cost air-quality monitors, such as the passive-diffusion tubes used by Barbican residents, and an increased awareness of local air quality, thanks to campaigns such as addresspollution.org (which allows UK citizens to check air pollution at their own address), could help to change that.
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The Barbican project, which was coordinated by social enterprise Mapping for Change, generated a host of local pollution-reduction policies, from anti-idling campaigns to urban greening. The Barbican became a pilot ‘low emission neighbourhood’ and, in March 2020, the City of London announced that Beech Street, a pollution hotspot, would become the UK’s first 24/7 zero-emission street in an 18-month trial that ended last September. In February, Mapping for Change completed its second year-long air pollution monitoring project, six years on from the first. ‘There was a marked reduction in the nitrogen dioxide levels that we’ve been seeing over the course of the last year across the whole estate,’ says Louise Francis, co-founder and managing director of Mapping for Change. ‘In Beech Street, where we previously had readings in excess of 100 micrograms per cubic metre, we were getting readings in the region of 25–27. That’s a massive drop off.’
There’s no easy way to remove pollution once it’s in the air; Bloss describes it as like trying to separate the milk from the water after serving a coffee. The most effective policies focus on reducing emissions. Bloss says the government’s targets need to be much more ambitious, particularly in terms of their timescale. ‘I think we’re just now beginning to go over the peak of the nitrogen dioxide challenge as we begin to see electric vehicles and clean vehicles on the roads. But the fine particles challenge still remains.’
Since Beech Street reopened to petrol and diesel vehicles last year, the levels of nitrogen dioxide have crept back up to between 50 and 70 micrograms per cubic metre. Francis says some of this could be attributed to higher traffic levels as more people returned to work, and further analysis of the data will be needed to paint a clearer picture. Meanwhile, Mapping for Change has been sending diffusion tubes as far away as Scotland to support other resident groups. ‘We’re just so glad to see more and more communities being able to do this and then to use this information and hard data to inform decisions and try to influence policy at a local level.’
